Waters Xevo G2-XS QTof Overview And Maintenance Manual page 7

High temperature hazard
The source ion block, located behind the source enclosure
Warning:
assembly, can become hot. To avoid burn injuries, ensure the source
heater is turned off and the ion block is cool before performing
maintenance on these components.
Mass spectrometer high temperature hazard:
Source ion block assembly
April 2, 2015, 715004496 Rev. B vii